Sound-insulating plate, sheet, or slab



May 10, 1927. I I J. wElss sown msum'rme PLATE, SHEET, on SLAB Patented -May 10, 1927.

UNITED STATES Jomimms warss, or LEIrzIe, GERMANY.

. SOUND-INSULATING PLATE, SHEET, ,OR SLAB.

I Application filed September 26, 1824; Serial No. 740,148.

It is a common practice' to use elastic sheets, slabs or plates in the foundat ons of machinery and engines, and also in buildings and so on, for the purpose of reducing vibration and insulating sound, various substances and fabrics being used for making such sheets, slabs or plates, for example felt,

cotton and woollen fabrics, cork, paper, peat,

rubber, feathers and so on'. Such sheets, may for example be placed between'a ma chine and the floor or foundation on which it stands, or may be placed under a bed or foundation plate.

lVith the methods. hitherto used it has been found that to obta n complete, or practically complete insulation of sound an absorption of vibration the sheets must be made of a thickness which in practice isgenerally quite out of the uestion.

According to my invention this difficulty is overcome by so constructing a sheet, slab or plate of elastic material, for the purpose stated, that the load bearing or resting thereon not only compresses the mater al, or POI: tions thereof, but imposes primarily a bending stress; that isto say the formation of the sheet is such that a load rest ng thereon does not merely tend to flatten it out, or condense the material but bends over certain portions of the sheet, which may be ribs, bosses, webs orthe like, as Wlll be explained hereinafter.

The invention is illustrated in the accompanying drawings, showing several examples.

Figs. 1 to 5 are cross sections, each showing one example embodying the novel feature and Figs. 6 to 9 are plan views showing other examples. I

Referring first to Fig. 1 it will be seen that there are parallel, inclined ribs a on the upper surface of the plate I) forming the body or base of the sheet. The sheet may be of rubber or any other elastic material or composition which lends itself to the making of a sheet of this kind, and 1s of adequate strength and durability for the purpose. dicate the manner in which the elastic ribs are bent over to one side by a load resting on the sheet.

Broken lines in the drawing 'in- According to Fi 2 the body or web 5 of the sheet has inc ined ribs (1 on its upper surface, and ribs inclined in the same direction on its under side.

In the modification shown in Fig. 3 the web I) has on its upper side ribs (1 inclined towards the right, and on itsunder side ribs (1 inclined towards the left.

The ribs are not necessarily in one piece with the web, and they need not be oi the same material as the web. In use, the load may rest directly upon the ribs, or a cover of wood, concrete, or any other suitable materlal may be interposed between the ribs and the load which the sheet is to hear. I

It will beapparent' that the bendin of the ribs by the load imposes on the. ri s a ben'dingstress which greatly impedes transmission or vibration. Of course the load,

acting on the web or body ofthe sheet throughthe ribs, also compresses the mater'al and the compressed material assists in absorbing or damping vibration, but the absorption of vibration by acompressed elastic body is very much less than the absorption by a body of the same material under bending stress, and I have found that a good insulatin effect is obtainable with plates of this kind of a thickness which would be practically useless .for insulating purposes with a plain, smooth plate.

In the modification shown in Fig. 4; the sheet 0? plate is built up of strips 0 and 0 of elastic material joined to each other side by side, the strips 0 alternating with the strips 0 and being wider than they, so that a series of parallel ribs is formed on the sheet. In shape this sheet is similar to that shown in Fig. 1, the only difference being that it is not made in one piece.

Accordin to Fig. 5 the sheet ismadeon the sheet. The channels may be straight.

or curved. In this modification the top and bottom surfaces of the sheet are smooth.

In the example shown in Fig. 6 the'ribs a) extend in straight lines parallel with two edges of the sheet, whereas in Fig. 7 the ribs a are zigzag.

In Fig. 8 inclined bosses a are-substituted for ribs.

to secure by Letters Patent of the United States is A slab or plate for the purpose'set forth comprising a sheet of elastic material and slab or ,plate an elastic members horizontally apart and each making onone side an acute angle with the plane of said on the opposite side an obtuse angle with said plane.

In witness whereof I specification.

J OHANNES WEISS.

joined to said sheet, spaced l0 have signed this 15 

